Field of the Invention
The present invention relates to a method, a recording medium and an electronic device of geolocation. More particularly, the present invention relates to a method, a recording medium and an electronic device of 3D geolocation.
Description of the Related Art
Geolocation utilizing mobile network RAN (radio access network) signaling is getting more and more attention from telecom mobile operators. By utilizing geolocation results of all the subscribers in the network, monitored 24 by 7, it can save a lot of human time, effort and cost to optimize and troubleshoot the network problems by traditional drive test method. Furthermore, traditional drive test can only cover a certain area (public roads/streets) and a certain time period while running drive test. It is usually difficult to duplicate the exact same problems the subscribers encounter.
For 2G mobile networks such as GSM (Global System for Mobile Communications) and CDMA (code division multiple access), 3G mobile networks such as UMTS (Universal Mobile Telecommunications System), CDMA2000 and TD-CDMA (time-division-code division multiple access), 4G mobile networks such as LTE (Long Term Evolution) and WiMAX (Worldwide Interoperability for Microwave Access), and coming 5G mobile networks, 3GPP (The 3rd Generation Partnership Project) defines the series of signaling protocol specifications for the communication between user equipment, base station (cell site) and core network. By utilizing the signaling messages, there are many well-known 2D-geolocation methods such as trilaterization, triangulation, multilateration and also many fine-tune proprietary patents for 2D-geolocation. However, in modern cities, there are more and more tricky RF (radio frequency) problems caused by high buildings. Knowing the latitude and longitude is not enough anymore and 3D-geolocation is still a big challenge.
Even in traditional GPS (Global Positioning System) geolocation, 3D-geolocation accuracy is not good either. For example, the accuracy in GPS latitude and longitude could be as good as several meters up to 20 meters error. However, the accuracy in GPS vertical dimension could be up to hundreds of meters error. If the similar approach is applied to telecom mobile network, the traditional GPS positioning method is not so practical because of two reasons. The first reason is that the accuracy in vertical dimension is too sensitive and dozens of meters could already lead to 10 floors error which is not acceptable. The second reason is that, unlike GPS satellites measurement, usually a user equipment in a mobile network can hardly measure 4 or more cell sites. The best practice average is that less than 5% of the calls can measure 4 or more sites. The valid 3D geolocation samples are too few because of the limited number of measured cell sites.